Reaction apparatuses utilizing affinity detection, which uses a substance that selectively binds to a specific molecule for selectively detecting a substance that corresponds to the molecule, have been developed. For example, Japanese Unexamined Patent Application Publication No. 2002-202305 (Patent Document 1) discloses an affinity detection/analysis chip having a structure in which a plurality of capillaries having inner surfaces to which a probe molecule that specifically binds to an analyte to be detected is immobilized are bundled and discloses a detection system.
Specifically, in the detection system disclosed in Patent Document 1, a sample to be analyzed is allowed to flow in the plurality of capillaries so that an analyte molecule contained in the sample binds to the capillary inner surfaces through a specific bond between the analyte molecule and the probe molecule. The bond formed in the insides of the capillaries is observed and analyzed using a light absorption observation device.